Multi-stage wash system for vat polymerization-based 3d printed parts

ABSTRACT

The invention is generally a system for washing off residual resin from objects which are three-dimensionally (3D) printed through a vat polymerization (VP) process. Exemplary systems may include a solvent receptacle, a wash reservoir in fluid communication with the solvent receptacle, and a controller configured to pump a solvent from the solvent receptacle to the wash reservoir for washing off residual resin from a 3D-printed object. Exemplary methods may include pumping a first solution of a plurality of solvent solutions from the solvent receptacle to the wash reservoir, dispersing the first solution onto the 3D-printed object, pumping the first solution from the wash reservoir to the solvent receptacle, pumping a second solution of the plurality of solvent solutions from the solvent receptacle to the wash reservoir, and dispersing the second solution onto the 3D-printed object.

PRIORITY AND RELATED APPLICATIONS

This application is a continuation of U.S. Non-Provisional applicationSer. No. 17/142,942, filed on Jan. 6, 2021, which claims priority toU.S. Provisional Application No. 62/957,645, filed on Jan. 6, 2020, thedisclosure of which is incorporated by reference in their entirety.

TECHNICAL FIELD OF THE INVENTION

The present invention primarily relates to a system for washing off theuncured or residual resin from objects which are three-dimensionally(3D) printed. Particularly, the present invention relates to amulti-stage wash system for use in removing residual resin from objectsthat are 3D-printed through a vat polymerization (VP) process.

COPYRIGHT AND TRADEMARK NOTICE

A region of the disclosure of this patent application may containmaterial that is subject to copyright protection. The owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightswhatsoever.

Certain marks referenced herein may be common law or registeredtrademarks of third parties affiliated or unaffiliated with theapplicant or the assignee. Use of these marks is by way of example andshould not be construed as descriptive or to limit the scope of thisinvention to material associated only with such marks.

BACKGROUND OF THE INVENTION

Three-dimensional printing, also known as additive manufacturing (AM),rapid prototyping (RP), or solid freeform fabrication (SFF), is anadvanced manufacturing process to additively create 3D objects fromcomputer-aided design (CAD) data directly. The machine which performsthe process is called a 3D printer. Compared with traditionalmanufacturing processes, such as milling, drilling, and injectionmolding, in which the object is fabricated through removing excessmaterial from a block or changing the shape of the material, 3D printingfabricates 3D objects through selectively depositing material or energyon a single layer, and then accumulating layers one upon another to form3D objects. Because of its unique means to create 3D objects, parts withcomplex shapes and intricate geometric features, which are usually notaccessible through traditional manufacturing processes, could befabricated through 3D printing. 3D printing is a collection of differenttechniques including vat polymerization, fused deposition modeling(FDM), selective laser sintering (SLS), etc.

Vat polymerization is one of the most popular 3D printing processes inthe market nowadays. It uses a solution which is a mixture ofphotosensitive monomer and/or oligomer and certain photo initiator asthe raw material. This photosensitive material may be a resin which isoriginally in the liquid state. When the resin is exposed to a lightsource with a certain wavelength, the photo initiator inside the resinmay reach excited state to create a reactive specie, e.g., a freeradical, a cation, or an anion. The reactive specie opens the π-bond ofthe monomer or oligomer and appends itself to the monomer or oligomer toform a new radical, cation, or anion. This process is repeated, and manymore monomers and/or oligomers are successively added to the reactivespecies to form a polymer with a crosslinked network. In this process,the state of the resin turns from liquid into solid.

Vat polymerization process creates 3D objects by selectively solidifythe resin layer by layer. Depending on the light source, there areseveral major types of VP processes, including stereolithography(SLA)-based VP which uses a laser as the light source, digital lightprocessing (DLP)-based VP, and liquid crystal display (LCD)-based VP.All of these types of VP processes use liquid resin as the raw materialand form 3D objects from a resin vat.

In VP processes, as 3D objects are created from the liquid resincontainer, and the printing part and/or the platform need to be immersedor partially immersed into the liquid resin, it is inevitable thatresidual resin in the liquid state stays on the surface of the 3Dprinted parts. Usually, a wash process is necessary to remove all theresidual resin before sending the 3D printed parts for post curing,otherwise, the accuracy could be compromised. This is because theresidual resin gets cured in a position during post curing, whichresults in an incremental change in dimensions of the object.

Furthermore, after being solidified, the hardened polymers are almostnon-toxic, however, the exposure to uncured resin can be harmful, and itmay contain a substance that is toxic and/or carcinogenic. Thus, it isdesirable to have a wash process, through which the uncured or residualresin is completely removed from the surface of 3D printed parts, tocomplement the VP-based 3D printing processes.

Compared with other 3D printing technologies, VP-based 3D printing isone of the most accurate processes. Because of this, it is also one ofthe most popular processes in the market. With the advancement oftechnology and enhancement in printing speed, resolution, andreliability, VP-based 3D printing has been widely used in various fieldsrecently, including dentistry, orthodontics, audiology, and jewelry. Asa result, the necessity of some peripherals which can smoothen andfacilitate the post process of VP-based 3D printing becomes more andmore prominent. Similar to other commercial products, these peripheralsare expected to be compact, efficient, reliable, user friendly, easy tooperate, and cost effective.

Accordingly, it would be highly desirable to develop a wash system forVP-based 3D printing processes to fulfill the requirement in commercialapplications and improve on the efficiency and efficacy of theconventional washing systems. It is to these ends that the presentinvention has been developed.

BRIEF SUMMARY OF THE INVENTION

According to the present invention, a wash system and method forremoving the uncured or residual resin from the surface of objects whichare created through a vat polymerization-based 3D printing process andremoving residual wash solvent from the surface of the 3D printedobjects, is described. The residual resin and wash solvent removalprocess described in the present invention includes multiple stages, anddifferent stages serve different purposes. The multi-stage wash systemfor vat polymerization 3D printed parts is efficient, reliable, and easyto operate.

There are two major families of base monomers used in VP processes: 1)acrylicmethacrylic-based resin which can be crosslinked through radicalpolymerization; and 2) epoxy or vinyl ether-based resin which can becrosslinked through cationic polymerization. To remove the uncured orresidual resin on the surface of 3D printed objects, traditionally,repetitive baths with chemicals, including acetone, isopropyl alcohol(IPA), or tripropylene glycol monomethyl ether (TPM), are used. Theentire process of the bath can be broken down into the following steps:

1. Refill the wash reservoir with a predetermined volume of washsolvent;

2. Immerse the 3D printed objects with residual resin on their surfaceinto the wash solvent;

3. Agitate the wash solvent for a certain period of time;

4. Take out the 3D printed objects from the wash reservoir; and

5. Air-dry the objects.

Depending on the result after wash at step 3, it may be necessary togive the 3D printed objects another round of wash to achievesatisfactory cleanliness. A final rinse with water may also be engagedinto the entire wash process to remove the trace of the wash solventused for baths.

In terms of the method adopted for agitating the wash solvent, there aretwo types of agitating methods: contact and non-contact. In contactstirring, a stirring device, such as a propeller or a magnetic bar, maybe directly placed into the wash solvent, and it spins quickly toagitate the wash solvent when a rotating motor or a rotating magneticfield is employed. In non-contact stirring, nothing is in direct contactwith the wash solvent. Instead, it creates turbulence in the washsolvent through an external mechanical oscillator or ultrasoundoscillator.

A wash system for cleaning 3D objects printed through VP-based 3Dprinting processes may broadly comprise of a cartridge or receptaclethat is used to store the wash solvent, a wash reservoir in which theremoval of uncured resin from the surface of 3D printed objects happens,an automatic stirring device to agitate the wash solvent to wash off theuncured resin more efficiently, and an air-drying system.

According to some exemplary embodiments of the present invention, asystem for removing the residual resin from the surface of objects whichare created through a vat polymerization-based 3D printing process andremoving residual wash solvent from the surface of objects, maycomprise: a wash solvent reservoir or receptacle; a wash reservoir influid communication with the wash solvent receptacle; and a controllerconfigured to pump a wash solvent from the wash solvent receptacle tothe wash reservoir for washing off residual resin from objects that are3D printed through a VP process.

According to some exemplary embodiments of the present invention, asystem for washing 3D printed objects may include a resin concentrationmonitoring module.

According to some exemplary embodiments of the present invention, asystem for washing 3D printed objects may include a wash reservoir withan anti-splashing adapter for a build platform to prevent wash solventfrom splashing or spilling from the wash reservoir.

According to some exemplary embodiments of the present invention, asystem for washing 3D printed objects may include multiple pumps torefill or drain the wash reservoir, including automatic valves to directand control the flow of the wash solvent, and or check valves to preventan unwanted reverse flow of the wash solvent.

According to some exemplary embodiments of the present invention, asystem for washing 3D printed objects may include an observation windowthrough which the user can observe the whole process.

According to some exemplary embodiments of the present invention, asystem for washing 3D printed objects may include a wash reservoir withone inlet and one outlet which are used to refill and drain the washreservoir, respectively. The inlet and outlet may include barbs tosecurely fasten the tubing and prevent leakage. The wash reservoir mayalso include a mesh which is expected to prevent printed 3D printedobjects or parts thereof from directly hitting a rotatory componentduring a wash or air-drying process. The material of the mesh may bepreferably compatible with both the wash solvent and the resin. Thebottom of the wash reservoir may be slightly slanted and coated with athin layer of hydrophobic and/or oleophobic coating, e.g., Teflon, tohelp drain the wash reservoir completely.

According to some exemplary embodiments of the present invention, asystem for washing 3D printed objects may include an adapter for thewash reservoir on which the build platform from a specific VP-based 3Dprinter can directly sit. The adapter may include an anti-splashingdesign, so the agitated wash solvent cannot come out of the washreservoir during the wash process, however, it allows the necessarycirculation of the air flow during the air-drying process.

According to some exemplary embodiments of the present invention, asystem for washing 3D printed objects may include a resin concentrationmonitoring module for measuring the resin concentration of the washsolvent in real time. The resin concentration monitoring module givesfeedback to the entire wash system based on which the wash system candetermine whether the wash solvent is suitable for wash or needs to bereplaced. After each wash, the uncured resin goes into the wash solvent,and thus, the resin concentration in the wash solvent increases. Thewash solvent used in the present invention is preferably configured formultiple uses and may be repeatedly used until the resin concentrationreaches a certain level beyond which the wash process is not efficientanymore. Accordingly, in some exemplary embodiments, a user may berequired to replace the wash solvent. This may be achieved in variousmanners depending on the specifications of the resin concentrationmonitoring module. For example, and without limiting the scope of thepresent invention, the following are exemplary embodiments of a resinconcentration monitoring module in accordance with the presentinvention:

Detecting Change in Density:

For a commonly used wash solvent, such as acetone, IPA, or TPM, itsdensity is usually smaller than that of the resin. To be more specific,the density for acetone is 0.788×10³ kg/m³, the density for IPA is0.785×10³ kg/m³, and the density for TPM is 0.975×10³ kg/m³. Comparedwith the density of the aforementioned solvents, the density forphotosensitive resin is usually greater than 1.1×10³ kg/m³. When morephotosensitive resin is dissolved into the wash solvent, the density ofthe wash solvent also increases. Based on the change of the wash solventdensity, a density-based sensor, e.g., hydrometer, can be used tomonitor the resin concentration in the wash solvent.

Detecting Change in Pressure:

Besides directly using density change to indicate the resinconcentration of the wash solvent, the pressure change at a certainlocation can also be used for this purpose. The pressure (P) in a staticliquid is proportional to both the liquid density (ρ) and the depth (h)in the liquid which can be represented as P=ρgh, where g is thegravitational constant. Therefore, the pressure change at a certaindepth in the wash solvent can reflect the wash solvent density change,and further indicate the concentration change of the wash solvent.

Detecting Change in Opacity:

Another method to monitor the concentration change of the wash solventis to evaluate the opacity of the wash solvent. For commonly used washsolvent, such as acetone, IPA, or TPM, it usually has a hightransparency. With the increasing of the resin concentration, thetransparency decreases. This change can be detected by a photosensitivesensor, such as a photoresistor. For a given light source, theresistance of a photoresistor increases with decreasing incident lightintensity which is caused by increasing media opacity between the lightsource and the photoresistor. Therefore, the opacity can be used toindicate the resin concentration in the wash solvent.

According to some exemplary embodiments of the present invention, asystem for washing 3D printed objects may include a predetermined volumeof wash solvent. The wash solvent may be added into the wash reservoirthrough an auto refilling system which includes a pump, valves andtubing. Before the wash process starts, the pump may transport the washsolvent from the wash solvent reservoir to the washing reservoir untilthe predetermined volume is achieved. A liquid level measuring modulecan be used to check the volume of the wash solvent and determinewhether to stop feeding the wash reservoir.

In some exemplary embodiments, the aforementioned photosensitive sensorcan also serve to monitor whether the predetermined volume is achieved.The photosensitive senor may be mounted at a certain height on the washreservoir which reflects the predetermined volume. Before the washsolvent reaching that height, the gap between the photosensitive sensorand the light source is filled with air. Once the liquid level achievesthat height, the same gap is filled with the wash solvent whosetransparency is usually lower than that of the air. This change intransparency can be monitored by a photosensitive sensor, such as aphotoresistor. Once the drop in the transparency is observed, the autorefilling system stops feeding the wash reservoir. Therefore, the volumein the wash reservoir is the predetermined amount.

According to some exemplary embodiments of the present invention, asystem for washing 3D printed objects may be configured for removingresidual wash solvent from the surface of objects after the washprocess. The residual wash solvent removal process introduced by thepresent invention may include an air-drying system. The air-dryingsystem may be compact, reliable and easy to operate.

According to some exemplary embodiments of the present invention, asystem for washing 3D printed objects may include solvent cartridgesthat are removable and replaceable to store the wash solvent. Thecartridges may be compact and interchangeable.

According to some exemplary embodiments of the present invention, asystem for washing 3D printed objects may be configured to perform amulti-stage residual resin removal process, e.g., two stages:preliminary wash and fine wash. The majority of the residual resin,i.e., 85%, 90%, or 95%, may be removed during the preliminary wash, andthe remaining liquid resin on the 3D printed objects, i.e., 15%, 10%, or5%, may be washed off during the fine wash. In some embodiments, thewash solvent for each wash stage comes from an exclusive or separatewash solvent cartridge or solvent compartment in a solvent receptacle.

According to some exemplary embodiments of the present invention, asystem for washing 3D printed objects may be configured to perform amulti-style residual resin removal process, i.e., rinsing, splashing,and jetting. Different wash styles may stem from the wash solvent leveland the liquid flow rate. In a rinsing style, the 3D printed objects maybe fully immersed into the wash solvent, and the wash solvent may beagitated gently. In this case, the residual resin may be removed mainlyby dissolving into the wash solvent. In a splashing style, an agitatormay be immersed into the wash solvent, and the wash solvent may beagitated with a medium speed. In this case, the residual resin may beremoved by both dissolving into the wash solvent and washing off by thesolvent flow. In a jetting style, the liquid level may be lower than theagitator, and the wash solvent may be agitated with a high speed. Inthis case, the residual resin may be removed mainly by washing off bythe high-speed solvent flow. Generally, jetting is more effective thansplashing, and splashing is more effective than rinsing. However, higheragitating rates may cause more solvent loss for each wash. Therefore,the material property and resin concentration in the wash solvent mayneed to be taken into consideration when selecting the wash style foreach stage.

According to some exemplary embodiments of the present invention, asystem for washing 3D printed objects may be configured to adaptivelychange the duration for each wash stage based on the resin type, theresidual resin amount, the resin concentration in the wash solvent, andthe wash style.

According to some exemplary embodiments of the present invention, amethod for washing off residual resin from objects that are 3D-printedthrough a vat polymerization process, and removing residual wash solventfrom the surface of the 3D printed objects, may include pumping a firstsolution of a plurality of solvent solutions from a solvent receptacleto a wash reservoir of the system, wherein the wash reservoir is adaptedto enclose a 3D-printed object, by activating a pump of solventdisperser adapted to facilitate a flow of the plurality of solventsolutions between the wash reservoir and the solvent receptacle;dispersing the first solutions onto the 3D-printed object by activatingan agitator of the solvent disperser adapted to disperse the pluralityof solvent solutions onto the 3D-printed object; pumping the firstsolution from the wash reservoir to the solvent receptacle in order tosubstantially remove the first solution from the wash reservoir; pumpinga second solution of the plurality of solvent solutions from the solventreceptacle to the wash reservoir; and dispersing the second solutiononto the 3D-printed object.

According to some exemplary embodiments of the present invention, amethod in accordance with the present invention may include activatingan agitator to create an airflow and dry the 3D-printed object.

According to some exemplary embodiments of the present invention, amethod in accordance with the present invention may include filling upthe wash reservoir with a solution so that the 3D-printed object insidethe wash reservoir is fully submerged in the solvent during a rinsingcycle.

According to some exemplary embodiments of the present invention, amethod in accordance with the present invention may include filling upthe wash reservoir with a solution so that a propeller of the agitatoris fully submerged in the solvent during a splashing cycle.

According to some exemplary embodiments of the present invention, amethod in accordance with the present invention may include filling upthe wash reservoir with a solution so that a solvent level inside thewash reservoir is lower than a portion of a propeller of the agitatorduring a jetting cycle.

According to some exemplary embodiments of the present invention, amethod in accordance with the present invention may include monitoring aresin concentration inside the solvent receptacle using one or moresensors including an optical sensor, a density sensor, or a pressuresensor.

Various objects and advantages of the present invention will becomeapparent from the following description taken in conjunction with theaccompanying drawings wherein are set forth, by way of illustration andexample, certain embodiments of this invention. The drawings submittedherewith constitute a part of this specification, include exemplaryembodiments of the present invention, and illustrate various objects andfeatures thereof.

BRIEF DESCRIPTION OF DRAWINGS

Elements in the figures have not necessarily been drawn to scale inorder to enhance their clarity and improve understanding of thesevarious elements and embodiments of the present invention. Furthermore,elements that are known to be common and well understood to those in theindustry are not depicted in order to provide a clear view of thevarious embodiments of the invention.

FIG. 1A is a block diagram of an exemplary system for removing theuncured residual resin from the surface of objects which are createdthrough a vat polymerization-based 3D printing process, in accordancewith the present invention.

FIG. 1B is a block diagram of another exemplary system for removing theuncured residual resin from the surface of objects which are createdthrough a vat polymerization-based 3D printing process, in accordancewith the present invention.

FIG. 2 is a perspective view of a multi-stage wash system for VP-based3D printed parts according to an embodiment of the present invention.

FIG. 3 is a front view of wash solvent cartridge according to anembodiment of the present invention.

FIG. 4 is a front cross-sectional view of a wash solvent cartridgeaccording to an embodiment of the present invention.

FIG. 5 is a block diagram of a controller according to an embodiment ofthe present invention.

FIG. 6 is a schematic diagram for an exemplary pump, valve, and tubingsystem according to an embodiment of the present invention.

FIG. 7 is a front perspective view of a wash reservoir according to anembodiment of the present invention.

FIG. 8 is a bottom perspective view of a wash reservoir according to anembodiment of the present invention.

FIG. 9 is a front perspective view of an anti-splashing adapteraccording to an embodiment of the present invention.

FIG. 10 is a front sectional view of an anti-splashing adapter accordingto an embodiment of the present invention.

FIG. 11A-FIG. 11B depict an exemplary embodiment of the presentinvention in which a top aperture of a multi-stage wash device isconfigured to receive a platform of a 3D printer that can be washedusing the system when coupled to the aperture.

FIG. 12A-FIG. 12C depict a front view and side views, respectively, ofthe exemplary embodiment illustrated in FIG. 11A-FIG. 11B.

FIG. 13 depicts a cross-sectional view along the segment S-S illustratedin FIG. 12A.

FIG. 14A-FIG. 14C depict a first perspective side view, a top view, anda second perspective side view, respectively, of an exemplary embodimentof the present invention.

FIG. 15A-FIG. 15C depict a first side view, a front view, and a secondside view, respectively, of the exemplary embodiment illustrated in FIG.14A-FIG. 14C.

FIG. 16-FIG. 21 depict several see-through and cross-sectional viewsshowing various components and configurations of the components withinan enclosure of a device in accordance with exemplary embodiments of thepresent invention.

FIG. 22 illustrates an exemplary enclosure for housing the componentsdepicted in FIG. 16-FIG. 21.

FIG. 23A-FIG. 23C depict a first perspective side view, a top view, anda second perspective side view, respectively, of an exemplary embodimentof the present invention that employs a cage for enclosing 3D printedobjects therein.

FIG. 24A-FIG. 24B depict a first exploded perspective side view, and asecond exploded perspective side view of the exemplary embodimentillustrated in FIG. 23A-FIG. 23C.

FIG. 25A-FIG. 25C depict an exploded view and exploded side views,respectively, of the exemplary embodiment illustrated in FIG. 23A-FIG.24B.

FIG. 26A-FIG. 26B depict an exploded front view and a bottom view,respectively, of an exemplary wash reservoir including a cage adapted toenclose a 3D printed object therein.

FIG. 27A-FIG. 27B depict an exploded cross-sectional view along thesegment A-A of FIG. 26A and an exploded side view thereof, respectively,of an exemplary wash reservoir including a cage adapted to enclose a 3Dprinted object therein.

FIG. 28 depicts an exploded perspective view of exemplary wash reservoirincluding a cage adapted to enclose a 3D printed object therein.

FIG. 29 depicts a cross-sectional view of one exemplary embodiment for awash reservoir including a solvent disperser module configured todisperse solvent within a wash reservoir in accordance with the presentinvention.

FIG. 30 depicts a cross-sectional view of some exemplary components of asolvent disperser module in accordance with the present invention.

FIG. 31A depicts a perspective view of a solvent disperser assemblyhousing a motor in a sealed configuration.

FIG. 31B depicts an exploded view of the components of the solventdisperser assembly depicted in FIG. 31A.

FIG. 32A-FIG. 32B depict a perspective view and a cross-sectional viewof an airway or airflow system in accordance with some exemplaryembodiments of the present invention.

FIG. 33A-FIG. 33B depict a cross-sectional view and a close-upcross-sectional view, respectively, of an enclosure monitoring system inaccordance with some exemplary embodiments of the present invention.

FIG. 34A-FIG. 34B depict a perspective view and a cross-sectional viewof a vortex breaker in accordance with some exemplary embodiments of thepresent invention.

FIG. 35A-FIG. 35C depict a front view and side views, respectively, ofthe exemplary embodiment illustrated in FIG. 11A-FIG. 11B, the housingshown in a sealed configuration with a top lid in the closed position.

FIG. 36-FIG. 37 depict cross-sectional views along line segments D-D andK-K as shown in FIG. 35A.

FIG. 38-FIG. 42 depict a top view, and several perspective views of anexemplary embodiment of the present invention in which two removablecartridges serve as repositories for two solutions kept separatelyadjacent to the washing cavity.

FIG. 43 depicts a perspective view of an exemplary embodiment of thepresent invention that employs a quick-connect valve system forefficiently removing solvent from one or more solvent reservoirs.

FIG. 44A-44B depict components for a quick-connect valve system inaccordance with the present invention.

FIG. 45 depicts a quick-connect valve system in use, in accordance withpractice of the present invention.

DESCRIPTION OF THE INVENTION

In the following discussion that addresses a number of embodiments andapplications of the present invention, reference is made to theaccompanying drawings that form a part thereof, where depictions aremade, by way of illustration, of specific embodiments in which theinvention may be practiced. It is to be understood that otherembodiments may be utilized, and changes may be made without departingfrom the scope of the invention. Wherever possible, the same referencenumbers are used in the drawings and the following description to referto the same or similar elements.

In the following detailed description, numerous specific details are setforth by way of examples in order to provide a thorough understanding ofthe relevant teachings. However, it should be apparent to those skilledin the art that the present teachings may be practiced without suchdetails. In other instances, well known structures, components and/orfunctional or structural relationship thereof, etc., have been describedat a relatively high-level, without detail, in order to avoidunnecessarily obscuring aspects of the present teachings.

Throughout the specification and claims, terms may have nuanced meaningssuggested or implied in context beyond an explicitly stated meaning.Likewise, the phrase “in one embodiment/example” as used herein does notnecessarily refer to the same embodiment and the phrase “in anotherembodiment/example” as used herein does not necessarily refer to adifferent embodiment. It is intended, for example, that claimed subjectmatter include combinations of example embodiments in whole or in part.

Conditional language used herein, such as, among others, “can,” “could,”“might,” “may,” “e.g.,” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain embodiments include, whileother embodiments do not include, certain features, elements and orsteps. Thus, such conditional language is not generally intended toimply that features, elements and or steps are in any way required forone or more embodiments, whether these features, elements and or stepsare included or are to be performed in any particular embodiment.

The terms “comprising,” “including,” “having,” and the like aresynonymous and are used inclusively, in an open-ended fashion, and donot exclude additional elements, features, acts, operations and soforth. Also, the term “or” is used in its inclusive sense (and not inits exclusive sense) so that when used, for example, to connect a listof elements, the term “or” means one, some, or all of the elements inthe list. Conjunctive language such as the phrase “at least one of X, Y,and Z,” unless specifically stated otherwise, is otherwise understoodwith the context as used in general to convey that an item, term, etc.may be either X, Y, or Z. Thus, such conjunctive language is notgenerally intended to imply that certain embodiments require at leastone of X, at least one of Y, and at least one of Z to each be present.The term “and or” means that “and” applies to some embodiments and “or”applies to some embodiments. Thus, A, B, and or C can be replaced withA, B, and C written in one sentence and A, B, or C written in anothersentence. A, B, and or C means that some embodiments can include A andB, some embodiments can include A and C, some embodiments can include Band C, some embodiments can only include A, some embodiments can includeonly B, some embodiments can include only C, and some embodimentsinclude A, B, and C. The term “and or” is used to avoid unnecessaryredundancy. Similarly, terms, such as “a, an,” or “the,” again, may beunderstood to convey a singular usage or to convey a plural usage,depending at least in part upon context. In addition, the term “basedon” may be understood as not necessarily intended to convey an exclusiveset of factors and may, instead, allow for existence of additionalfactors not necessarily expressly described, again, depending at leastin part on context.

While exemplary embodiments of the disclosure may be described,modifications, adaptations, and other implementations are possible. Forexample, substitutions, additions, or modifications may be made to theelements illustrated in the drawings, and the methods described hereinmay be modified by substituting, reordering, or adding stages to thedisclosed methods. Thus, nothing in the foregoing description isintended to imply that any particular feature, characteristic, step,module, or block is necessary or indispensable. Indeed, the novelmethods and systems described herein may be embodied in a variety ofother forms; furthermore, various omissions, substitutions, and changesin the form of the methods and systems described herein may be madewithout departing from the spirit of the invention or inventionsdisclosed herein. Accordingly, the following detailed description doesnot limit the disclosure. Instead, the proper scope of the disclosure isdefined by the appended claims.

As used in this disclosure, the term “comprise” and variations of theterm, such as “comprising” and “comprises”, are not intended to excludeother additives, components, integers or steps.

For purpose of description herein, the terms “upper”, “lower”, “left”,“right”, “front”, “rear”, “horizontal”, “vertical” and derivativesthereof shall relate to the invention as oriented in figures. However,it is to be understood that the invention may assume various alternativeorientations and step sequences, except where expressly specified to thecontrary. It is also to be understood that the specific devices andprocesses illustrated in the attached drawings, and described in thefollowing specification are simply exemplary embodiments of theinventive concepts defined in the appended claims. Hence, specificdimensions and other physical characteristic relating to the embodimentsdisclosed herein are not to be considered as limiting, unless the claimsexpressly state otherwise.

Turning now to the figures, FIG. 1A is a block diagram of an exemplarysystem for removing the uncured residual resin from the surface ofobjects which are created through a vat polymerization-based 3D printingprocess, in accordance with the present invention. More specifically,FIG. 1A depicts system 100, comprising a wash solvent storage orreceptacle 10, a controller 20, and a solvent disperser module 30, whichmay include one or more of a pump, valve(s), and tubing or conduitsconfigures to supply the wash reservoir with a wash solvent stored inthe wash receptacle, and a wash reservoir 40 in which 3D printed objectsmay be washed. The wash solvent receptacle 10 stores wash solvent forremoving the residual resin from the 3D objects which are 3D printedthrough a VP-based process. The wash solvent could be acetone, IPA, TPMor water (for water-washable resin). The controller 20 controls theentire wash and air-drying process, including refill and drain the washreservoir 40, switch on and off the agitator for wash and air-drying,etc. The pump, valve, and tubing system of solvent disperser module 30provides the necessary power and passage to direct and transport therequired wash solvent for a specific wash stage from the wash solventreceptacle 10 to the wash reservoir 40, or in the opposite direction,i.e., from the wash reservoir 40 to the wash solvent receptacle 10. Thewash reservoir 40 receives the wash solvent from the wash solventreceptacle 10 and provides a space where wash and air-drying processestake place.

FIG. 1B is a block diagram depicting some exemplary components of system100 in accordance with the present invention. More specifically, FIG. 1Bdepicts system 100 exemplarily, and without limiting the scope of thepresent invention, including a resin concentration monitoring module 10a, a user interface 20 a, an agitator 30 a, a pump/valve system 30 b, aventilation or airflow system 40 a, and a support platform 40 b.

In some exemplary embodiments, which will be discussed in more detailbelow, a resin concentration monitoring module 10 a may include one ormore sensors 10 b for detecting a resin concentration within washsolvent receptacle 10. This allows system 100 to detect when the solventmay need replenishment or changing. As will be discussed below, severaltypes of sensors may be utilized without deviating from the scope of thepresent invention, including optical sensors, density sensors, pressuresensors, or any other type of sensor that may be suitable for detectinga resin concentration in order to monitor that the solvent being used isadequate for washing off the undecided residue from 3D printed objects.

In some exemplary embodiments, which will be discussed in more detailbelow, the controller 20 may include a user interface 20 a for a user toprogram, execute, or otherwise control features of system 100. Userinterface 20 a may be as simple as a few buttons or more complex such asa display with a touch screen. Several embodiments of a user interfacein accordance with the present invention will be discussed with moredetail below.

In some exemplary embodiments, which will be discussed in more detailbelow, the solvent disperser module may include various components,including an agitator that may be adapted for dispersing the solvent inone or multiple manners so as to maximize the washing process. Forexample, and without limiting the scope of the present invention, system100 may include an agitator 30 a that is configured to disperse solventin a jetting manner, a splattering manner, and in an immersive manner.In some exemplary embodiments, the agitator may comprise of a propeller.Each means of dispersing a solvent onto a 3D printed object will bediscussed with more detail below.

In some exemplary embodiments, which will be discussed in more detailbelow, the wash reservoir may include various components, including aventilation or airflow system 40 a for improving or facilitating anairflow within the wash reservoir. Such airflow system may facilitate adrying cycle or drying sequence activated by controller 20 to dry offthe 3D printed object after one or more wash cycles.

In some exemplary embodiments, which will be discussed in more detailbelow, the wash reservoir may include a support platform 40 b forsupporting a 3D printed object being washed therein. In some exemplaryembodiments, support platform 40 b may include an adapter for securing a3D printer platform, or other 3D printer component directly onto theadapter (see FIG. 2, FIG. 11A-FIG. 13). In some exemplary embodiments,support platform 40 b may include a cage (see FIG. 24A-FIG. 28, forexample) for enclosing the 3D printed object and preventing debris fromthe residue that comes off the 3D printed object from interfering withcomponents of system 100.

FIG. 2 depicts a perspective view of a two-stage wash apparatus forremoving the uncured residual resin from the surface of 3D objects whichare created through a vat polymerization-based 3D printing processaccording to an embodiment of the present invention. More specifically,FIG. 2 depicts one embodiment of system 100, which includes an enclosure50 that houses each of the components of system 100 to provide aneasy-to-use appliance to the user. Enclosure 50 may be a singleenclosure with multiple cavities therein, and or may be configured tohold one or more receptacles or containers therein. For example, andwithout limiting the scope of the present invention, enclosure 50 mayinclude a first cavity for housing wash reservoir 40, which may besituated within a larger area or cavity of the enclosure 50. Enclosure50 may include a second cavity for housing wash solvent receptacle 10,which may be situated within a smaller area or cavity of the enclosure50. Disposed on or accessible via an outer surface of enclosure 50, maybe user interface 20 a, which allows a user to interact with system 100.Controller 20 and solvent disperser module 30 may be housed within theone or more cavities of enclosure 50 along with any other components ofsystem 100. Enclosure 50 may be configured to receive components ofsystem 100 therein, such as for example, cartridges that may form partor facilitate use of solvent receptacle 10, in accordance with someexemplary embodiments of the present invention, as will be discussedwith reference to FIG. 3 and FIG. 4 below.

Turning now to the next set of figures, FIG. 3 is a front view of washsolvent cartridge according to an embodiment of the present invention;FIG. 4 is a front cross-sectional view of a wash solvent cartridgeaccording to an embodiment of the present invention; FIG. 5 is a blockdiagram of a controller according to an embodiment of the presentinvention; and FIG. 6 is a schematic diagram for an exemplary pump,valve, and tubing system according to an embodiment of the presentinvention.

According to some exemplary embodiments, as depicted in FIG. 6, the washsolvent receptacle 10 may include two repositories for storing twosolvent solutions. In one exemplary embodiment, as shown and inaccordance with the cartridges illustrated in FIG. 3 and FIG. 4, the tworepositories may comprise cartridges, i.e., a wash solvent cartridge forthe preliminary wash 11 a and wash solvent cartridge for the fine wash11 b. Referring to FIG. 3-4, each cartridge may include two bite valves,i.e., 111 for the inlet and 112 for the outlet, which are located on theunderside of the wash solvent cartridge 11, i.e., the bite valves 111 aand 112 a for the cartridge 11 a, the bite valve 111 b and 112 b for thecartridge 11 b. When the cartridge 11 is installed in position, the bitevalve 111 and 112 are squeezed to allow the wash solvent to flow intothe tubing connected to the cartridge 11. Once the cartridge 11 isremoved from the wash system, the bite valve 111 and 112 return to itsoriginal state and shuts off the flow.

The wash solvent cartridge 11 is made from material which is compatiblewith both resin and wash solvent, such as poly(methyl methacrylate)(PMMA).

Referring to FIG. 3-FIG, 4, each cartridge may also include an ID chipwhich is located next to the bite valve 111. The ID chip may be used tosave and update the information related to the wash solvent it contains,such as the type of the wash solvent and the current resin concentrationof the solvent. When the cartridge 11 is installed in position, thecontroller 20 reads the information from the ID chip. Based on thisinformation, the wash system can determine the style and time for eachwash stage.

Referring to FIG. 5, the controller 20 may include a circuit board 501,which integrates electronic components comprising a micro control unit(MCU 502), memory 503, and I/O ports 504. Necessary program and data areinstalled in the memory for MCU 502 to operate. In exemplaryembodiments, memory 503 incudes a set of executable instructions foroperating the system 100.

Referring to FIG. 2, in accordance with some exemplary embodiments, thecontroller 20 may also include a touch screen (user interface 20 a),which may be electrically connected with the circuit board of FIG. 5 ashuman-machine interface. Its major functions include, but are notlimited to:

-   -   a. receiving commands from the user, such as start a programmed        wash cycle, start a customized wash cycle, set the customized        time for each wash stage, drain the wash bucket 41, cancel the        job, etc;    -   b. showing the status of the wash system, e.g., busy or idle;    -   c. showing the progress regarding to current job, e.g., stage 1        wash, stage 2 wash, or air-drying;    -   d. showing the relevant information regarding to current job,        e.g., estimated time consumption, estimated time left, resin        concentration for wash solvent cartridge 11 a, resin        concentration for wash solvent cartridge 11 b, etc.; and or    -   e. showing system relevant information, such as machine model        number, machine serial number, etc.

The concept of multi-stage wash is implemented by a pump, valve, andtubing system that form part of the disperser module 30 which fluidlycommunicates the wash solvent receptacle 10 with the wash reservoir 40.Referring to FIG. 6, in one exemplary embodiment, such as system 600, atwo-stage wash system may employ the pump, valve, and tubing system ofthe disperser module 30, including a refill pump 31, a drain pump 32, an“L” type automatic three-way valve 33 for the refill pump 31, an “L”type automatic three-way valve 34 for the drain pump 32, a check valve35 connected with the wash solvent inlet 44 of wash reservoir 40 (seealso FIG. 8), a check valve 36 connected with the wash solvent outlet 45of wash reservoir 40 (see also FIG. 8), and tubing 37 that forms part ofthe pump, valve, and tubing system of the disperser module 30.

In some exemplary embodiments, a wash and air-drying process may bebroken down into the following steps:

-   -   Step 1: The “L” type three-way valve 33 switches the direction        to allow the wash solvent to flow from the cartridge or tank 11        a of receptacle 10 to the refill pump 31;    -   Step 2: The refill pump 31 pumps a predetermined volume of wash        solvent from the cartridge or tank 11 a of receptacle 10 to the        wash reservoir 40;    -   Step 3: The agitator 30 a runs for a specific time for a        preliminary wash (i.e., although the agitator is not shown in        the diagram of FIG. 6, see other figures for reference such as        FIG. 13 and FIG. 18, in which an agitator is shown housed within        the wash reservoir);    -   Step 4: The “L” type three-way valve 34 switches the direction        to allow the wash solvent to flow from the drain pump 32 to the        cartridge or tank 11 a of receptacle 10;    -   Step 5: The drain pump 32 pumps the wash solvent from the wash        reservoir 40 back to the cartridge or tank 11 a of receptacle        10;    -   Step 6: The “L” type three-way valve 33 switches the direction        to allow the wash solvent to flow from the cartridge or tank 11        b of receptacle 10 to the refill pump 31;    -   Step 7: The refill pump 31 pumps a predetermined volume of wash        solvent from the cartridge or tank 11 b of receptacle 10 to the        wash reservoir 40;    -   Step 8: The agitator 30 a runs for a specific time for fine        wash;    -   Step 9: The “L” type three-way valve 34 switches the direction        to allow the wash solvent to flow from the drain pump 32 to the        cartridge or tank 11 b of receptacle 10;    -   Step 10: The drain pump 32 pumps the wash solvent from the wash        reservoir 40 back to the cartridge or tank 11 b of receptacle 10        so that wash reservoir is substantially empty and all or        substantially all of the solvent has been removed; and    -   Step 11: The agitator 30 a runs for a specific time for        air-drying.

Accordingly, in exemplary embodiments, a method performed by system 100for washing off residual resin from objects that are 3D-printed througha vat polymerization process, may include: pumping a first solution(stored in cartridge or tank 11 a) of a plurality of solvent solutionsfrom a solvent receptacle 10 to a wash reservoir 40 of system 100,wherein the wash reservoir 40 is adapted to enclose a 3D-printed object,by activating a pump of solvent disperser module 30 adapted tofacilitate a flow of the plurality of solvent solutions between the washreservoir 40 and the solvent receptacle 10; dispersing the firstsolutions onto the 3D-printed object by activating an agitator 30 a ofthe solvent disperser module 30 adapted to disperse the plurality ofsolvent solutions onto the 3D-printed object; pumping the first solutionfrom the wash reservoir 40 to the solvent receptacle 10 (i.e. acartridge or tank 11 a) in order to substantially remove the firstsolution from the wash reservoir 40; pumping a second solution (storedin cartridge or tank 11 b) of the plurality of solvent solutions fromthe solvent receptacle 10 to the wash reservoir 40; and dispersing thesecond solution onto the 3D-printed object.

In some exemplary embodiments, the method performed by system 100described above may further include: pumping the second solution fromthe wash reservoir 40 back to the solvent receptacle 10 (i.e., back intocartridge or tank 11 b) in order to substantially remove the secondsolution from the wash reservoir 40. In some exemplary embodiments, themethod performed by system 100 described above may further includeactivating the agitator 30 a of the solvent disperser module 30 tocreate an airflow and dry the 3D-printed object. In this manner, system,100 may be configured to perform an air-drying cycle.

See also FIG. 16-FIG. 20, which depict each of the components mentionedabove with reference to some exemplary embodiments of the presentinvention. In exemplary embodiments, the majority of the residual resinon the 3D printed object, i.e., 85%, 90%, or 95%, is expected to beremoved during the preliminary wash, and the remaining liquid resin onthe 3D printed objects, i.e., 15%, 10%, or 5%, is expected to be washedoff during the fine wash. The wash solvent for each wash stage may bestored in an exclusive wash solvent cartridge or tank of the solventreceptacle 10. Therefore, the resin concentration in the wash solventfor the preliminary wash increases much faster than that for the finewash, and as a result, it may require replacement more frequently aswell.

According to some exemplary embodiments of the present invention, asystem for washing 3D printed objects may be configured to perform amulti-style residual resin removal process, i.e., rinsing, splashing,and jetting. Different wash styles may stem from the wash solvent leveland the liquid flow rate. In a rinsing style, the 3D printed objects maybe fully immersed into the wash solvent, and the wash solvent may beagitated gently. In this case, the residual resin may be removed mainlyby dissolving into the wash solvent. In a splashing style, an agitatormay be immersed into the wash solvent, and the wash solvent may beagitated with a medium speed. In this case, the residual resin may beremoved by both dissolving into the wash solvent and washing off by thesolvent flow. In a jetting style, the liquid level may be lower than theagitator, and the wash solvent may be agitated with a high speed. Inthis case, the residual resin may be removed mainly by washing off bythe high-speed solvent flow. Generally, jetting is more effective thansplashing, and splashing is more effective than rinsing. However, higheragitating rates may cause more solvent loss for each wash. Therefore,the material property and resin concentration in the wash solvent mayneed to be taken into consideration when selecting the wash style foreach stage.

Referring to FIG. 6, the pump, valve, and tubing system of dispersermodule 30 includes a check valve 35 which is installed between therefill pump 31 and the wash solvent inlet 44. The check valve 35 allowsthe wash solvent to flow from the refill pump 31 to the wash solventinlet 44 and shuts off the flow in the opposite direction. The pump,valve and tubing system of disperser module 30 also includes a checkvalve 36 which is installed between the wash solvent outlet 45 and thedrain pump 32. The check valve 36 allows the wash solvent to flow fromthe wash solvent outlet 45 to the drain pump 32 and shuts off the flowin the opposite direction.

Referring to FIGS. 7-8, the wash reservoir 40 typically comprises a washbucket 41, wherein the wash bucket 41 may include a monitoring windowthat may be disposed over an aperture 41 a of the wash bucket 41, ananti-splashing adaptor 43, and a wash solvent inlet 44 that may includea barb, and a wash solvent outlet 45 that may include a barb forfacilitating coupling to the tubing system of disperser module 30.Although not shown in these views, but will be discussed further belowwith reference to other figures, wash reservoir 40 may typically houseor be coupled with a mesh, a resin concentration monitoring module, anda wash solvent agitator of the solvent disperser module 30.

In some exemplary embodiments, the wash bucket 41 may be made of amaterial that is compatible with both resin and wash solvent, such asPMMA. The wash bucket 41 may preferably employ a slightly slantedbottom, and the wash solvent outlet 45 may be located at its lowestposition. Therefore, this design can help to drain the wash solvent whennecessary. Furthermore, a hydrophobic and/or oleophobic coating, e.g.,Teflon, can be applied on the bottom of the wash bucket 41, which mayfurther help the drainage of the wash solvent. In some exemplaryembodiments, wash reservoir 40 including wash bucket 41 may employ amonitoring or observation window on one or more of the walls of washbucket 41, or the entirety of wash bucket 41 may be transparent, andthus, the user can monitor the wash and air-drying process. In suchembodiments, an enclosure of the system such as enclosure 50 may includesuch observation window on one of its walls.

Referring to FIG. 9-10, an anti-splashing adapter 43 sits on the top ofthe wash bucket 41. It receives the build platform from a specificVP-based 3D printer. The anti-splashing adapter 43 has an array of slots431, and below each slot 431, there is a small block 432 which isconnected to the bottom surface of the anti-splashing adapter 43.Therefore, no direct passage exists in the vertical direction for theanti-splashing adapter 43. When the wash solvent inside the wash bucket41 is agitated by the agitator, the wash solvent cannot come out easily.However, the slot 431 serves as a vent or airway for the necessary aircirculation during air-drying—that is, when the wash reservoir isemptied, and the agitator is activated to create an airflow that driesthe 3D-printed object within the wash reservoir. The inlet 44 and outlet45 of the wash reservoir 40 come with barbs or similar couplingcomponents, so the tubing with appropriate size can be securely fastenedon them.

Referring to FIG. 7, FIG. 11A-FIG. 11B, FIG. 13, and FIG. 24A-24B, oneor more components may be employed in order to protect the agitatorduring the wash and air-drying process. For example, and withoutdeviating from the scope of the present invention, in some exemplaryembodiments, a mesh may be positioned inside of wash bucket 41, whichprevents debris from falling back onto the agitator inside the washreservoir. In some exemplary embodiments, a support platform may beemployed. For example, and without deviating from the scope of thepresent invention, a support platform 40 b may be integrated with a lidof the wash reservoir, such as lid 1100, wherein the support platform 40b includes an adapter for receiving a build platform 1101 of a 3Dprinter. See for example the embodiment of FIG. 11A-FIG. 11B in whichlid 1100 includes a support platform 40 b that secures build platform1101 of a 3D printer. In this exemplary embodiment, a build platform ofa 3D printer may simply be placed facing into the wash reservoir 40 sothat 3D printed objects attached directly on the build platform for easeof use. In this exemplary embodiment, the attachment or the 3D printedobject may become loose during the wash and air-drying process due tothe impact from the wash solvent or air flow. Thus, it is possible thatthe 3D printed objects fall off from the build platform. Accordingly, asshown by way of example in FIG. 13, a mesh 1301 may be installed in thewash bucket 41 to prevent the fallen objects from directly hitting onthe agitator 30 a. Meanwhile, the bore size and density of the meshaffect the wash and air-drying efficiency. The selection of the boresize and density for the mesh needs to offer enough protection for therotatory components without significantly compromising the wash andair-drying efficiency. It is preferable that the bore size is in therange of 4-5 mm in diameter, the density is in the range of 4-6/cm², andthe thickness is less than 1 mm. The material of the mesh needs to becompatible with both the resin and wash solvent, such as stainless steel316L.

In some exemplary embodiments, instead of using a mesh, or even inaddition to a mesh, a support platform may employ include a cage orcontainer for containing the 3D-printed object therein. For example, andwithout limiting the scope of the present invention, FIG. 24A-24Billustrate such embodiment. From these views, it may be appreciated thata cage 2400 may be coupled to a lid that may be suspended over thecavity of wash reservoir 40. In FIG. 29 and in FIG. 33A exemplaryembodiments of a support or adapter configured to suspend a cage insidewash reservoir 40 are illustrated.

Referring to FIG. 2 and FIG. 7, a photosensitive-based resinconcentration monitoring module may be installed on the wash bucket 41.The resin concentration monitoring module may comprise a laser diode anda photoresistor. The laser diode can generate a light with a certainwavelength which illuminates the photoresistor. The resistance of thephotoresistor increases with decreasing incident light intensity whichis caused by increasing media opacity between the laser diode and thephotoresistor. The selection of the laser diode needs to avoid thewavelength range which may cause photopolymerization of the resin, suchas ultra-violet. In some exemplary embodiments, it may be preferable tohave a laser diode with a wavelength around 650 nm. The distance betweenthe laser diode and the photoresistor may be fixed, so readings of thephotoresistor are comparable and consistent. In some exemplaryembodiments, information regarding the resin concentration for the washsolvent from cartridge 11 a and 11 b could be saved and updated on an IDchip and, respectively, so the controller 20 can retrieve thisinformation when necessary.

The resin concentration monitoring module can also serve as the liquidlevel monitoring system. The resin concentration monitoring module canbe fixed at a certain height which reflects the expected liquid levelfor the wash solvent. Before the wash solvent reaches that height, thegap between the laser diode and the photoresistor is filled with airwhich usually has a higher transparency than that of the wash solvent.Once the wash solvent achieves that height, the resistance of thephotoresistor goes up, and it signals the controller 20 to stoprefilling the wash reservoir 40.

In some exemplary embodiments, the agitator agitates the wash solvent inthe wash bucket 41 to generate the turbulence with a predetermined speedfor a certain time to remove the uncured residual resin from the surfaceof the printed 3D objects. The agitator may also agitate the air whenthere is no solvent inside the wash bucket 41 to create air flow to drythe printed 3D objects after wash. In such embodiments, the agitatorcomprises a waterproof brushless motor and a propeller. In someexemplary embodiments, it may be preferable that the speed of thewaterproof brushless motor is in the rage of 5,000-25,000 rpm, and thelength of blade from the propeller is in the range of 45-55 mm.

There may be three types of wash style, i.e., rinsing, splashing, andjetting, depending on the liquid level of wash solvent. For the rinsingstyle, the 3D objects are fully immersed in the wash solvent. In thiscase, the residual resin on the 3D objects is mainly removed bydissolving into the wash solvent. For the splashing style, the liquidlevel of the wash solvent is higher than the highest point of thepropeller by 3-5 mm. In this case, the residual resin on the 3D objectsis removed by both dissolving into the wash solvent and washing off bythe solvent flow. For the jetting style, the liquid level of the washsolvent is lower than the lowest point of the propeller by 3-5 mm. Inthis case, the residual resin on the 3D objects is removed mainly bywashing off by the high-speed solvent flow. The benefit of jetting thesolvent versus rinsing are a) the amount of solvent used in jettingmethod is 10%-30% of the amount of solvent in rinsing (which is asignificant saving on the amount of solvent) and b) the jetting methodthrows the liquid with a speed to the model which leads to a moreeffective wash.

In this embodiment, a combination of time and style for each wash stagecould be determined based on the resin concentration of the wash solventused and the amount of residual resin on the 3D printed objects.

The resin concentration monitoring module gives feedback to the entirewash system based on which the wash system can determine whether thewash solvent is suitable for wash or needs to be replaced. After eachwash, the uncured resin goes into the wash solvent, and thus, the resinconcentration in the wash solvent increases. The wash solvent used inthe present invention is preferably configured for multiple uses and maybe repeatedly used until the resin concentration reaches a certain levelbeyond which the wash process is not efficient anymore. Accordingly, insome exemplary embodiments, a user may be required to replace the washsolvent. This may be achieved in various manners depending on thespecifications of the resin concentration monitoring module. Forexample, and without limiting the scope of the present invention, thefollowing are exemplary embodiments of a resin concentration monitoringmodule in accordance with the present invention:

Detecting Change in Density:

For a commonly used wash solvent, such as acetone, IPA, or TPM, itsdensity is usually smaller than that of the resin. To be more specific,the density for acetone is 0.788×10³ kg/m³, the density for IPA is0.785×10³ kg/m³, and the density for TPM is 0.975×10³ kg/m³. Comparedwith the density of the aforementioned solvents, the density forphotosensitive resin is usually greater than 1.1×10³ kg/m³. When morephotosensitive resin is dissolved into the wash solvent, the density ofthe wash solvent also increases. Based on the change of the wash solventdensity, a density-based sensor, e.g., hydrometer, can be used tomonitor the resin concentration in the wash solvent.

Detecting Change in Pressure:

Besides directly using density change to indicate the resinconcentration of the wash solvent, the pressure change at a certainlocation can also be used for this purpose. The pressure (P) in a staticliquid is proportional to both the liquid density (ρ) and the depth (h)in the liquid which can be represented as P=ρgh, where g is thegravitational constant. Therefore, the pressure change at a certaindepth in the wash solvent can reflect the wash solvent density change,and further indicate the concentration change of the wash solvent.

Detect Change in Opacity:

Another method to monitor the concentration change of the wash solventis to evaluate the opacity of the wash solvent. For commonly used washsolvent, such as acetone, IPA, or TPM, it usually has a hightransparency. With the increasing of the resin concentration, thetransparency decreases. This change can be detected by a photosensitivesensor, such as a photoresistor. For a given light source, theresistance of a photoresistor increases with decreasing incident lightintensity which is caused by increasing media opacity between the lightsource and the photoresistor. Therefore, the opacity can be used toindicate the resin concentration in the wash solvent.

Turning now to the set of figures FIG. 11A-FIG. 12C, an exemplaryembodiment of the present invention in which a top aperture of amulti-stage wash device is configured to receive a platform of a 3Dprinter that can be washed using the system when coupled to the apertureis depicted. FIG. 13 depicts a cross-sectional view of an exemplaryembodiment of the present invention in which a top aperture of amulti-stage wash device is configured to receive a platform of a 3Dprinter that can be washed using the system when coupled to theaperture. From these views, it may be appreciated that at the top of theapparatus, an aperture receives a portion of the platform in a manner sothat the surface(s) of the platform that require washing will be sealedinside the wash reservoir or cavity and facing the agitator. Asmentioned above, the agitator may also agitate air when there is nosolvent inside the wash reservoir (or wash bucket 41) to create air flowto dry the platform surface that has been washed.

Turning to figures, FIG. 14A-FIG. 15C, several perspective and sideviews are depicted of an exemplary embodiment of the present invention,showing a wash solvent reservoir opened. From these views, it may beappreciated that the wash solvent reservoir includes two adjacentrepositories for each of the solutions (i.e. a wash solution and a rinsesolution) employed by the system. For example, and without limiting thescope of the present invention, in such embodiment, rather thanutilizing a cartridge for each solution, the separated reservoirs withinthe wash reservoir is configured to separately hold the solutions in thetwo adjacent compartments. Further, in such embodiment, quick-connectvalves may be used to easily fill each compartment or reservoir with thesolution. This design may be desirable to save space and avoid the costsof the cartridges that may be employed in accordance with otherexemplary embodiments of the present invention. Notably, in eitherembodiment, the solutions are kept separated and never mixed outside ofthe wash reservoir also shown in these views. In one embodiment, the tworeservoirs are fixed and in another they are removeable.

Turning to the next set of figures, FIG. 16-FIG. 20 depict severalsee-through and cross-sectional views showing various components andconfigurations of the components within a housing of a device inaccordance with exemplary embodiments of the present invention. Variousvalves and pumps and sensors are shown in these views, which may beemployed in some exemplary embodiments of the present invention.

Draining the reservoirs and replacing the saturated solvent with a newsolvent may be achieved by the two quick connect fittings shown in FIG.16-FIG. 20. Quick connect fitting has a release mechanism that preventthe liquid from spilling upon shutting off. FIG. 16-FIG. 20 furtherdepict several see-through and cross-sectional views showing variouscomponents and configurations of the components within an enclosure of adevice in accordance with exemplary embodiments of the presentinvention.

As mentioned above and may be gleaned from FIG. 16-FIG. 20, a system1600 for washing off residual resin from objects that are 3D-printedthrough a vat polymerization process, in accordance with the presentinvention, may comprise: a wash reservoir 40 adapted to enclose a3D-printed object, the wash reservoir in fluid communication with asolvent receptacle 10, the solvent receptacle housing a plurality ofsolvent solutions; a solvent disperser module 30 including an agitator30 a and one or more pumps 31, 32, the agitator 30 a adapted to dispersethe plurality of solvent solutions onto the 3D-printed object and theone or more pumps 31, 32 adapted to facilitate a flow of the pluralityof solvent solutions between the wash reservoir 40 and the solventreceptacle 10; and a controller 20 (not shown but coupled to userinterface 20 a) in communication with the solvent disperser, thecontroller 20 including a set of executable instructions configured to:pump a first solution of the plurality of solvent solutions from thesolvent receptacle 10 to the wash reservoir 40; disperse the firstsolutions onto the 3D-printed object; pump the first solution from thewash reservoir 40 to the solvent receptacle 10; pump a second solutionof the plurality of solvent solutions from the solvent receptacle to thewash reservoir; and disperse the second solution onto the 3D-printedobject.

In exemplary embodiments, the controller 20 may be further configuredto: pump the second solution from the wash reservoir 40 to the solventreceptacle 10 thereby emptying the wash reservoir of any solventsolution. Subsequently, controller 20 may activate the agitator 30 a tocreate and airflow and dry the 3D printed object.

In some exemplary embodiments, the agitator 30 a comprises a propelleradapted to be fully or partially submerged in the first or secondsolvent solutions pumped into the wash reservoir 40—this may be achievedby forming a base or basin in which solvent solution may be gathered.

In some exemplary embodiments, the solvent receptacle comprises adjacenttanks 11 a and 11 b for separately holding two separate solutions. Insome exemplary embodiments, the adjacent tanks 11 a and 11 b maycomprise of cartridges. In some exemplary embodiments, system 1600further comprises a quick connect valves 1601 and 1602 for each of theadjacent tanks 11 a and 11 b of the solvent receptacle 10. In someexemplary embodiments, system 1600 further comprises a resinconcentration monitoring module configured to detect a resinconcentration inside the solvent receptacle 10. For example, and withoutdeviating from the scope of the present invention, the resinconcentration module may include one or more sensors 10 a including butnot limited to an optical sensor, and/or a density sensor, and/or apressure sensor.

To prevent spillage from the wash reservoir during operation of system1600, in some exemplary embodiments, system 1600 further comprises ananti-splashing adapter 43 situated on a top region of the wash reservoir40 (see also FIG. 7). In exemplary embodiments, the anti-splash adapterincludes openings for facilitating an airflow within wash reservoir 40during a drying cycle. In exemplary embodiments, as mentioned above,wash bucket 41 includes a slanted or angled surface 1603 to facilitatedraining any remaining solution from the wash reservoir during a wash ordry cycle or during cleaning.

A method, performed by system 1600 for washing off residual resin fromobjects that are 3D-printed through a vat polymerization process, forexample by system 1600, may include: (1) pumping a first solution of aplurality of solvent solutions from a solvent receptacle to a washreservoir of the system, wherein the wash reservoir is adapted toenclose a 3D-printed object, by activating a pump of solvent disperseradapted to facilitate a flow of the plurality of solvent solutionsbetween the wash reservoir and the solvent receptacle; (2) dispersingthe first solutions onto the 3D-printed object by activating an agitatorof the solvent disperser adapted to disperse the plurality of solventsolutions onto the 3D-printed object; (3) pumping the first solutionfrom the wash reservoir to the solvent receptacle in order tosubstantially remove the first solution from the wash reservoir; (4)pumping a second solution of the plurality of solvent solutions from thesolvent receptacle to the wash reservoir; and (5) dispersing the secondsolution onto the 3D-printed object.

In some exemplary embodiments, a method may further include (6) pumpingthe second solution from the wash reservoir to the solvent receptacle inorder to substantially remove the second solution from the washreservoir; and (7) activating the agitator to create an airflow and drythe 3D-printed object.

In some exemplary embodiments, a method may further include pumping thefirst solution or the second solution from the solvent reservoir to thewash reservoir comprises filling up the wash reservoir with the first orsecond solutions so that the 3D-printed object inside the wash reservoiris fully submerged in the solvent during a rinsing cycle.

In some exemplary embodiments, a method may further include pumping thefirst solution or the second solution from the solvent reservoir to thewash reservoir comprises filling up the wash reservoir with the first orsecond solutions so that a propeller of the agitator is fully submergedin the solvent during a splashing cycle. In some embodiments, thepropeller is full submerged by 3-5 mm.

In some exemplary embodiments, a method may further include pumping thefirst solution or the second solution from the solvent reservoir to thewash reservoir comprises filling up the wash reservoir with the first orsecond solutions so that a solvent level inside the wash reservoir islower than the lowest point of a propeller of the agitator during ajetting cycle. In some embodiments, the solvent level inside the washreservoir is lower than the lowest point of a propeller of the agitatorby 3-5 mm during a jetting cycle.

In some exemplary embodiments, a method may further include monitoring aresin concentration inside the solvent receptacle using one or moresensors including an optical sensor, a density sensor, or a pressuresensor.

Turning to the next set of figures, FIG. 21-FIG. 28 show a system thatemploys a cage 2400. More specifically, in these figures anotherexemplary embodiment is depicted in which a top is provided to cover theaperture of the washing reservoir instead of the platform receivingaperture shown in other figures discussed above. That is, an apparatusin accordance with the present invention may be configured to receiveparts inside a cage (i.e. in contrast with the embodiment in FIG.11-FIG. 12). The parts may be washed using the same methods and systemsin accordance with the present invention but in this version the partsare securely placed inside the cage rather than coupled directly to theaperture as is the case in the embodiment configured to receive a 3Dprinter platform. In some exemplary embodiments, the aperture isconfigured to receive both the platform and the lid shown in theseviews.

More specifically, FIG. 22 illustrates an exemplary enclosure forhousing the components depicted in FIG. 16-FIG. 21. FIG. 23A-FIG. 23Cdepict a first perspective side view, a top view, and a secondperspective side view, respectively, of an exemplary embodiment of thepresent invention that employs a cage for enclosing 3D printed objectstherein. FIG. 24A-FIG. 24B depict a first exploded perspective sideview, and a second exploded perspective side view of the exemplaryembodiment illustrated in FIG. 23A-FIG. 23C. FIG. 25A-FIG. 25C depict anexploded view and exploded side views, respectively, of the exemplaryembodiment illustrated in FIG. 23A-FIG. 24B.

FIG. 26A-FIG. 26B depict an exploded front view and a bottom view,respectively, of an exemplary wash reservoir including cage 2400 adaptedto enclose a 3D printed object therein. In this embodiment of theseviews, the wash system 2600 includes a lid 2601 and a cage 2400, whichfits inside wash reservoir 40. FIG. 26B depicts a bottom viewillustrating the bottom region of a motor assembly 2602 in accordancewith the present invention. The lid 2601 may include a lid handle 2603,and in exemplary embodiments, as shown in FIG. 29, a region of the lidextending into the interior of wash reservoir 40 may include a couplingmeans such as a retaining arm 2901 for suspending cage 2400 inside washreservoir 40.

FIG. 27A-FIG. 27B depict an exploded cross-sectional view along thesegment A-A of FIG. 26A and an exploded side view thereof, respectively,of an exemplary wash reservoir including a cage adapted to enclose a 3Dprinted object therein. FIG. 28 depicts an exploded perspective view ofexemplary wash reservoir including a cage adapted to enclose a 3Dprinted object therein. Moreover, the embodiment illustrated the figuresreferenced immediately above, may provide a more cost-effective andspace saving design. Further, this design may be more environmentallyfriendly since it avoids use of various cartridges that may have to berefilled or otherwise disposed of after use.

Now turning to the next figure, FIG. 29 depicts a cross-sectional viewof one exemplary embodiment for a wash reservoir including a solventdisperser module configured to disperse solvent within a wash reservoirin accordance with the present invention. More specifically, FIG. 29illustrates a motor assembly 2600 of a solvent disperser module inaccordance with the present invention. The motor assembly 2600 mayemploy a propeller 2902 to splash a liquid solvent 2903 upwards in amanner so that plenty of liquid will be dispersed on the 3D printedobject, largely washing away the resin residue. Dispersing may include,jetting, splashing, or otherwise directing a flow of the solvent ontothe 3D-printed part that may be suspended or secured within washreservoir 40. In some embodiments, the system may employ a wash cyclethat includes submerging or immersing the 3D printed object inside thewash reservoir, by for example, filling up the reservoir so that a 3Dprinted object therein is completely or substantially submerged, andactivating the propellor 2902 in order to create a flow of the solventliquid within the wash reservoir 40 and dislodge or remove any undesiredresidue.

In exemplary embodiments, for each cycle, the system consumes only 370ml liquid, and the wash takes 3 mins. The high running speed with 3000RPM of a brushless motor 2904, will drive the propeller to spin thesurrounding liquid up. Calculating the optimal volume of the liquidconsumed, this maximally releases the power of the brushless motor, andincreases the liquid exchange rate with the wash part surface. In someembodiments, a brushless motor selection with proper KV rating and speedsetting may deliver sufficient force of the liquid onto the part beingwashed. One benefit of this system is using a minimum volume of liquidto deliver the highest efficiency of wash result. Compared withconventional methods for washing, motor assembly 2600 highly increasesthe wash efficiency and wash cleanness results.

Turning now to the next figure, FIG. 30 depicts a cross-sectional viewof some exemplary components of a motor assembly for a disperser modulein accordance with the present invention. More specifically, FIG. 30depicts motor assembly 2600. To deliver a stable liquid dispersion, amotor 2904 drives an agitator, which in some exemplary embodiments asshown in this figure may comprise of a propeller 2902 to spin at stableRPMs. To deliver long-term usage, a seal may be preferably employed byassembly 2600, for example, and without limiting the scope of thepresent invention, a dynamic seal 3000. Dynamic seal 3000 may compriseof a rotary seal, or a power transmission seal. As may be appreciated bya person of ordinary skill in the art, dynamic seal 3000 is configuredto seal openings between a rotating and a stationary component.

FIG. 31A depicts a perspective view of motor assembly 2600 and FIG. 31Bdepicts an exploded view thereof. The motor assembly 2600 may includelock nuts 3101, that lock the propeller to the assembly, propeller 2902,propeller seat 3103, which is a collar that contains the set screw tosecure the propeller seat, a protecting O-ring 3104, a component forminimize the liquid flow into the seal, a grease component (notnumbered)—such as a chemical resistant grease to help isolate the liquidthat may traverse through the seal, a flange rotary seal 3106—a sealwith flange that is the primary seal surface—a spacer 3107, a bearing3108—a rotary assistant, a seal cover 3109, which is tightened by 4 M2screws and compresses the entire assembly, and a brushless motor 3110,which may be configured to run at 3000 rpm in some exemplaryembodiments, and which is the power source of the motor assembly 2600 todrive the propeller 2902.

Turning now to the next set of figures, FIG. 32A-FIG. 32B depict aperspective view and a cross-sectional view of an airway or airflowsystem in accordance with some exemplary embodiments of the presentinvention. More specifically, these figures depict a unique design of anairflow system 3200, which comprises of a lid or lid adapter thatprovides an air channel to deliver the air exchange system between thechamber or cavity of wash receptacle 40 and the exterior thereof, aswell as an anti-splash guard that may be built into the adapter. FIG.32B shows how a splash guard 3201 registers with a wash bucket 4 with aretaining arm 2901 that extends from a bottom region of the splash guard3201. Moreover, FIG. 32B depicts channel 3203 for providing an airflowor ventilation into the wash reservoir. In this embodiment, retainingarm 2901 extends from a bottom portion of splash guard 3201. The channel3203 of airflow system 3200 facilitates a flow of air when, for example,an air-drying cycle is performed by allowing a flow of air into and orout of wash reservoir 40.

Turning now to the next set of figures, FIG. 33A-FIG. 33B depict across-sectional view and a close-up cross-sectional view, respectively,of an enclosure monitoring system in accordance with some exemplaryembodiments of the present invention. More specifically, these viewsdepict enclosure monitoring system 3300, which may include a magnetsensor system designed to identify whether the wash lid or the platformis sitting flat. FIG. 33A shows the whole picture of the magnet sensorsystem with a wash bucket 3301. FIG. 33B is the detail section view ofhow the magnet sensors 3302 a, 3302 b may be positioned. For example,and without limiting the scope of the present invention, a first magnet3302 a is taped on the platform, and inserted into the groove of thewash lid. A second magnet 3302 b may be mounted on the outside of thewash bucket. When laying down the wash lid or the platform, the magnetwill create the hall effect, which enables a controller to read thesensor feedback and determine a position of the wash lid and orplatform. This user-friendly feature could protect the user when theyopen the wash lid or platform, the system will automatically pause toavoid the liquid splash out of the machine. Once the user places backthe wash lid or platform, the system will resume the process.

Turning to the next set of figures, FIG. 34A-FIG. 34B depict aperspective view and a cross-sectional view of a vortex breaker inaccordance with some exemplary embodiments of the present invention.More specifically, these figures show vortex breaker 3400, an exemplaryfeature that may be implemented on a base or surface of disperser module30 such as on a base portion of motor assembly 2600 of the dispersermodule 30. FIG. 34A illustrates how vortex breaker 3400 may be situatedas a replaceable part on a base 3401. The function of it is to stop theformation of the vortex when draining the liquid through one or moredrain holes that may be sealed and or controlled with a drain control3402. FIG. 34B depicts a cross-sectional view of the vortex breaker3400. The unique feature includes a twist knob 3403 of drain control3402, that is easy to remove by the user. By opening up knob 3403,drainage can be more efficiently achieved.

FIG. 35A-FIG. 35C depict a front view and side views, respectively, ofthe exemplary embodiment illustrated in FIG. 23A-FIG. 28, the housingshown in a sealed configuration with a top lid in the closed position.

FIG. 36-FIG. 37 depict cross-sectional views along line segments D-D andK-K as shown in FIG. 35A, illustrating the cage within the washreservoir. As may be appreciated from these views and as describedabove, during some cycles, the agitator such as a propeller of thewashing system may be completely submerged, partially submerged (as inFIG. 29) or completely above a solution or liquid level within the washreservoir of the system, depending on the cycle (i.e., the differentwash cycles, or an air-dry cycle).

FIG. 38-FIG. 42 depict a top view, and several perspective views of anexemplary embodiment of the present invention in which two removablecartridges serve as repositories for two solutions kept separatelyadjacent to the washing cavity. This design is an exemplary design inaccordance with embodiments discussed above, including as described withreference to FIG. 3-4, and FIG. 6.

FIG. 43 depicts a perspective view of an exemplary embodiment of thepresent invention that employs a quick-connect valve system forefficiently removing solvent from one or more solvent reservoirs.

FIG. 44A-44B depict components for a quick-connect valve system inaccordance with the present invention. As mentioned above, thequick-connect valves or fittings on an exterior of each reservoir may beused to easily drain or replace each of the solutions therein. Becausethe quick connect fittings have a release mechanism that prevent liquidfrom spilling upon shutting off, the components facilitate the drainingand replacement of procedure. Accordingly, this design may be desirableto save space and avoid the costs of the cartridges that may be employedin accordance with other exemplary embodiments of the present invention.Notably, in either embodiment, the solutions are kept separated andnever mixed outside of the wash reservoir also shown in these views.

In FIG. 44A, a quick disconnect system 4400 is illustrated in threeparts: the male quick disconnect 4401, a female quick disconnect 4402,and a female quick disconnect 4403. The function of this quickdisconnect fitting is to automatically shut-off liquid flow upondisconnection. FIG. 44B depicts a side view of the solvent reservoir 10,which may be slanted for easier cleaning as the slanting surface allowsfor easier drainage.

FIG. 45 depicts a quick-connect valve system in use, in accordance withpractice of the present invention. In FIG. 45, a flow path 4404 isreestablished when the couplings are connected (for example, male quickdisconnect 4401 to a female quick disconnect 4402); this feature allowsthe users to drain the liquid easily by inserting the quick disconnect,the insert will stay in place until manually push-pull out.

A multi-stage wash system for vat polymerization-based 3D printed partshas been described. The foregoing description of the various exemplaryembodiments of the invention has been presented for the purposes ofillustration and disclosure. It is not intended to be exhaustive or tolimit the invention to the precise form disclosed. Many modificationsand variations are possible in light of the above teaching withoutdeparting from the spirit of the invention.

What is claimed is:
 1. A method, performed by a system for washing offresidual resin from objects that are 3D-printed through a vatpolymerization process, comprising: pumping a first solution of aplurality of solvent solutions from a solvent receptacle to a washreservoir of the system, wherein the wash reservoir is adapted toenclose a 3D-printed object, by activating a pump of solvent disperseradapted to facilitate a flow of the plurality of solvent solutionsbetween the wash reservoir and the solvent receptacle; dispersing thefirst solutions onto the 3D-printed object by activating an agitator ofthe solvent disperser adapted to disperse the plurality of solventsolutions onto the 3D-printed object; pumping the first solution fromthe wash reservoir to the solvent receptacle in order to substantiallyremove the first solution from the wash reservoir; pumping a secondsolution of the plurality of solvent solutions from the solventreceptacle to the wash reservoir; and dispersing the second solutiononto the 3D-printed object.
 2. The method of claim 1, furthercomprising: pumping the second solution from the wash reservoir to thesolvent receptacle in order to substantially remove the second solutionfrom the wash reservoir; and activating the agitator to create anairflow and dry the 3D-printed object.
 3. The method of claim 1,wherein: pumping the first solution or the second solution from thesolvent reservoir to the wash reservoir comprises filling up the washreservoir with the first or second solutions so that the 3D-printedobject inside the wash reservoir is fully submerged in the solventduring a rinsing cycle.
 4. The method of claim 3, wherein: pumping thefirst solution or the second solution from the solvent reservoir to thewash reservoir comprises filling up the wash reservoir with the first orsecond solutions so that a propeller of the agitator is fully submergedin the solvent during a splashing cycle.
 5. The method of claim 3,wherein: pumping the first solution or the second solution from thesolvent reservoir to the wash reservoir comprises filling up the washreservoir with the first or second solutions so that a solvent levelinside the wash reservoir is lower than a portion of a propeller of theagitator during a jetting cycle.
 6. The method of claim 1, furthercomprising: monitoring a resin concentration inside the solventreceptacle using one or more sensors including an optical sensor, adensity sensor, or a pressure sensor.